1. Field of the Invention
The present invention is in the field of providing integrated series connections of a plurality of photovoltaic thin film solar cells arranged on a common, isolating transparent substrate. Separating grooves are introduced into the thin film for the manufacture of electrically conductive connections between the individual solar cells and are filled with metal during manufacture of the back electrodes. The front electrode of one cell is thus connected to the back electrode of the neighboring cell.
2. Description of the Prior Art
A solar cell arrangement similar to that of the present invention is described, for example, in U.S. Pat. No. 4,517,403.
One of the principal problems, both in the manufacture of the solar cell, as well as in its later employment, is the contacting of the solar cells to each other. Usually, the n-conductive zone of one solar cell is connected in electrically conductive fashion to the p-conductive zone of an adjoining solar cell, the connection being by means of contact connectors of metal, such as silver. With solar cells of single crystal silicon, an external discrete wiring of the cells usually takes place, and this requires a considerable outlay of work.
Thin film solar cells of, for example, amorphous silicon (a-Si:H, amorphous silicon with bonded hydrogen atoms) can be generated on an insulating carrier. Due to the slight conductivity of the transparent front electrode, a plurality of small individual cells must be connected in series in the manufacture of large module surfaces in order to avoid losses of efficiency and in order to increase the module voltage. This is possible in the very simple way due to the basic common substrate. Strip shaped cells having operating voltage of, for example, about 0.7 volts can be formed. Cells having operating voltages of, for example, 12 to 24 volts, when series connected can thus be produced in the production sequence of cell manufacture.
The problem thus is to combine the series connection with the cell manufacture in a relatively simple way without deteriorating the efficiency of the solar cell.
The Fifth E.C. Photovoltaic Solar Energy Conference Proceedings, Kavouri, Greece, October 1983, pp. 712-716, as well as the Seventeenth IEEE Photovoltaic Conference, Orlando, Fla. 1984, pp. 206-211, disclose that a selective laser parting method can be employed for series connection of such thin film solar cells. In this method, known as laser scribing, the selective parting of the amorphous silicon layer and the subsequent selective parting of the metallized portions produces greater technical difficulty. In addition, methods involving laser systems are extremely costly.